Facilitating exercise using externally applied, transcutaneous stimulation, including by sending electrical pulses to contract or otherwise activate the targeted or involved muscles, is known in the art. Typically, the electrical pulses applied are generated by an external stimulator, and travel through associated wires to one or more electrode pairs placed on the skin adjacent the muscle(s) to be contracted. The electricity passing through the skin causes the targeted muscle fibers to activate or contract, even without voluntary control by the subject. Accordingly, such stimulation is frequently used in situations where the subject is incapacitated or otherwise unable to control function of the muscles, such as in the event of an injury to the brain or associated portion of the nervous system.
Despite the past use of electrical stimulation for exercising muscles, certain limitations in the application of this technology and the results produced remain. For one, no known device at present allows an exercise subject in need of rehabilitation to perform a seated (or “recumbent”) alternating leg extension (or “stepping”) exercise with the application of electrical stimulation. Such a regimen is considered especially beneficial for those in need of exercise for purposes of strengthening, retraining, or overall well being, but unable to walk or even stand for the time necessary to meet this need. A seated stepping exercise also better simulates the exercise movements needed to walk than, for example, a pedaling exercise using a stationary bicycle. Furthermore, completing such an exercise provides a sense of accomplishment in terms of simulating the ability to walk without the concomitant problems and sense of failure felt by those who cannot walk but might attempt to do so with the application of stimulation.
However, applying stimulation to the legs to create an alternating, or bi-lateral stepping pattern, is not a straightforward task. With a stationary bicycle, in which momentum drives the exercise, stimulation bursts may be applied to one leg simply to provide sufficient momentum to cause the other leg to also move as the result of the interconnected pedals. However, repeated stepping cannot be accomplished solely by applying such stimulation bursts to the individual legs. Also, stimulation generally cannot be used to retract the legs from an extended position. Hence, the mere application of a burst of stimulation alternately to a sitting subject's legs would simply lead to nothing productive in terms of providing the benefits of the stepping exercise and the concomitant sense of accomplishment.
Accordingly, a need is identified for a manner in which to combine the benefits achieved through electrical muscle stimulation with those of a stepping exercise, including for subjects with a full or partial inability to use the muscles of their lower extremities (and, in particular, one or both of their legs).